"It's more efficient than trying to heat you up by heating the air around you," Covell says.

Jones was inspired by heated floors and mattress pads, and indeed, he created an efficient lounge. The plug-in-ready four-seater draws about as much energy as a hair dryer at 1,500 watts. The electric heating elements are fully integrated, cycling on and off to regulate temperature.

"It's like a highly functional brain," Jones says.

Built for the outdoors, the Helios Lounge's "brain" is sealed in a weatherproof casing.

Measuring 94 inches long and 2 1/2 feet tall, the lounge weighs about 250 pounds. The cast-stone surface, which comes in five colors, sits on a powder-coated steel base. While ideal for the purposes of outdoor heating and making the seat's curved shape, concrete proved to be a great ergonomic challenge.

"The trouble with concrete is that it conforms well to a mold, but not to a body," Covell says.

Jones tinkered and tested at TechShop, the do-it-yourself fabrication workshop in SoMa, molding and shaving off concrete to ensure the lounge would be comfortable for all shapes and sizes.

Covell and Jones, both San Francisco transplants, plan to keep things local. The concrete comes from Oakland, the base from Newark, and each lounge is handmade in San Francisco. For buyers in the area, the Helios Lounge is delivered and installed. The lead time is eight to 10 weeks.

Before forming their company, Covell & Jones, CEO Covell, originally from Missouri, worked in business, product development and marketing in San Francisco for 13 years. Creative Director Jones, from Montana and recently in school in Arizona, has been designing in San Francisco for three years. The Helios Lounge is his first design to go into production, and he's looking forward to adding more items to the Helios furniture line later this year.

The Helios Lounge, $4,900 at www.galanterandjones.com. Lounges can be seen by appointment at the Galanter & Jones Studio at 715 Bryant St., No. 103, San Francisco, (415) 763-7322, or at Flora Grubb Gardens, 1634 Jerrold Ave., San Francisco.